1. Field of the Invention
The present invention is related to phacoemulsification needles and more specifically, to irrigation sleeves surrounding the needles for use in ophthalmic surgery.
2. Description of Related Art
It is well known to remove cataracts from a patient's eyes, and replace the removed cataract affected lenses with artificial intraocular lenses. It is common and accepted practice to remove the cataract affected lenses via phacoemulsification.
Phacoemulsification enables a lens to be removed from the eye through a small incision, typically on the order of 3 mm. Phacoemulsification involves using high frequency ultrasonic energy transmitted through a handpiece into a phacoemulsification needle to fragment the affected lens. Once the lens is fragmented or emulsified, the lens material is aspirated, along with irrigation fluid through a lumen of the phacoemulsification needle, and through the handpiece and into a collection reservoir of a surgical system.
During aspiration of the lens material, it is typical to simultaneously insert a flow of irrigation fluid into the eye. This flow is provided to prevent the eye from collapsing during aspiration and to prevent serious damage to the eye from such collapse. It is also typical that a phacoemulsification needle provides what is commonly referred to as coaxial irrigation. This coaxial irrigation provides the flow of irrigation fluid into the eye via a resilient sleeve surrounding the needle. The irrigation sleeve typically includes circular irrigation ports adjacent to the distal end of the sleeve so that fluid flows from the handpiece in between the sleeve and the outside of the needle and through the circular ports. While phacoemulsification and coaxial irrigation have proven to be very successful and safe, there are some drawbacks, which may be improved upon.
One such drawback is that because of the prior art's circular shaped irrigation ports, when the irrigation sleeve becomes compressed upon insertion into an incision in the eye, the trailing edge of the circular port tends to flare-out and therefore, increase the cross-sectional area or footprint that must be inserted past the incision in the eye. This flaring of the trailing edge tends to cause the sleeve to bunch-up and not be properly inserted into the eye, particularly into a tight wound. A tight wound or a small incision is often preferred to minimize the damage to the eye, and to also provide a maximum amount of sealing around the sleeve of the needle to prevent loss of fluids from the surgical site.
Therefore, it would be desirable to have an irrigation sleeve with a port shape, which would not have a flaring trailing edge and therefore, be easier to insert into an eye's incision.